This application relates to automatic test equipment (ATE) pin electronics circuits for testing integrated circuit devices. Examples of ATE systems and/or components thereof are set forth in the following U.S. patents, all of which are incorporated by reference: U.S. Pat. No. 5,673,275, U.S. Pat. No. 5,225,772, and U.S. Pat. No. 5,212,443.
In ATE used to test integrated circuit devices, pin electronics circuits are coupled to the pins or other nodes of an integrated circuit device being tested, typically referred to as the “device under test” or DUT. Through the pins, stimuli signals or waveforms are supplied to the DUT, and output signals or waveforms from the DUT are detected and measured. Typically, the stimuli signals or waveforms represent logic states or analog voltages or currents, which generally are applied to the pins of the DUT in parallel, with the resulting output signals read in parallel.
Many different types of electrical tests can be applied to DUT pins. Different kinds of pin electronics circuits typically are used to apply these different types of tests. Examples of tests that may be applied to DUT pins include the following:
Digital Test—this test typically includes a sequence of test vectors, described according to industry standard definitions such as the Standard Tester Interchange Language (STIL) defined in Institute of Electrical and Electronics Engineers (IEEE) specification 1450, in which a DUT's input pins are driven to HIGH or LOW logic levels according to the contents of the vector, and the DUT's output pins are measured to determine whether the output voltage is above or below a specified logic threshold level. This test is executed at a time appropriately defined for each vector in the sequence.
Continuity Test—this test determines whether an electrical connection exists between the pin electronics circuit and a DUT input, output, or input/output (“I/O”) pin.
Voltage Output High (VOH) Test—this test measures the HIGH logic level output voltage when a specified current is applied to a DUT output pin.
Voltage Output Low (VOL) Test—this test measures the LOW logic level output voltage when a specified current is applied to a DUT output pin.
Input Current High (IIH) Test—this test measures the current required to drive a DUT input pin to a specified HIGH logic level. This test may be referred to as a “leakage test.”
Input Current Low (IIL) Test—this test measures the current required to drive a DUT input pin to a specified LOW logic level. Like IIH tests, this test also may be referred to as a “leakage test.”
Continuity tests, voltage tests, and current tests, such as those discussed above, typically are made using a Parametric Measurement Unit (PMU) in conjunction with pin electronics circuits. The PMU is an instrument that can force voltage and measure current, and/or force current and measure voltage. Characteristics of a PMU include resolution, range, performance, and programmable limits. Resolution refers to the ability to generate or measure small differences in voltage or current. Range refers to the highest and lowest voltages or currents that the PMU can generate or measure. Performance refers to the number of measurements of all types that can be made per unit of time. Programmable limits refer to the ability to set limitations on the current or voltage range so that devices being tested are not damaged by the PMU.
Conventional pin electronics circuits typically have individual circuits separately available to conduct tests, such as those described above. Such conventional pin electronics circuits generally include a driver circuit that generates preprogrammed logic levels, one or more comparator circuits to measure output levels, a preprogrammed load circuit that forces a voltage-dependent current to be drawn from or pushed into the DUT pin, and a PMU, which can be programmed to apply a specific current and measure the resulting voltage or alternatively to apply a specific voltage and measure the resulting current.